Will 4.5 hours be enough time to walk from the train station to the main sights in Wismar such as the Nikolaikirche, the Marienkirche, the Kirche St. Georgen, the marktplatz, and back? This would be in June. Thx for any opinions and thoughts!
Look at a map (like http://www.unser-stadtplan.de/stadtplan/wismar/kartenstartpunkt/stadtplan-wismar.map) and you'll see that it's all close to the railway station. Those 4,5 hours give you ample time, including a beer or coffee at the Marktplatz.
Thank you! (I very much enjoyed walking around Leiden last year! I did a day trip from Haarlem.)